Embodiments relate to a waveguide and, more particularly, to a system and method to provide for interchanging a dielectric filter within a waveguide without further permanent physical alterations being made to the waveguide.
In electromagnetics and communications, the term “waveguide” refers to any linear structure that conveys electromagnetic waves between its endpoints. Waveguides are metallic transmission lines that are used at microwave frequencies, typically to interconnect transmitters and receivers (transceivers) with antennas. Waveguides have a number of advantages over coax, microstrip and stripline. One such advantage is that waveguides are completely shielded, thus an excellent isolation between adjacent signals can be obtained. Another advantage is that waveguides can transmit extremely high peak powers while having very low loss (often almost negligible) at microwave frequencies.
One type of waveguide is a hollow metal pipe used to carry radio waves referred to herein as a hollow waveguide. Other types of waveguides include dielectric waveguides that employ a solid dielectric rod or filter within the hollow opening. Another dielectric waveguide may be optical fibers in which the dielectric guide is designed to work at optical frequencies. Transmission lines such as microstrip, coplanar waveguide, stripline or coaxial may also be considered to be waveguides, however these waveguides have two conductors.
Hollow waveguides are commonly used as a transmission line at microwave frequencies in microwave waveguide hardware, such as for connecting microwave transmitters and receivers to their antennas. A standard hollow waveguide structure is a hollow metal tube or rectangle that distributes electrical inductance at its walls and capacitance in the space between its walls. Waveguide propagation modes depend on the operating wavelength and polarization as well as a shape and size of the hollow waveguide. Hollow waveguides must be one-half wavelength in the dielectric or more in diameter at the frequency one wishes the waveguide to support transmission in order to support one or more transverse wave modes. The shape and dimensions of the hollow waveguides thus determines its frequency, bandwidth, impedance and rejection.
Hollow waveguides are generally made so that the waveguide has a solid outer wall or surface with an opening through a center along its longitudinal axis. When a filter is machined to a part of the waveguide (integral with the waveguide), removing the filter results in damaging, or potentially damaging the waveguide. Microwave waveguide hardware may require a change to a center frequency, bandwidth, impedance or rejection due to changing applications, or a change if the microwave hardware does not work as it was designed. Currently, making such a change requires remachining or other processing to the hollow waveguide itself to provide the desired performance change.
Users of such waveguides and manufacturers would benefit from a system and method changing frequency, bandwidth, impedance or rejection associated with a waveguide filter. Having an insertable or interchangeable dielectric filter does not require making permanent physical alterations to the waveguide.